<?php
// +----------------------------------------------------------------------
// | TOPThink [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2010 http://topthink.com All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: 麦当苗儿 <zuojiazi@vip.qq.com> <http://www.zjzit.cn>
// +----------------------------------------------------------------------
// | ImageGd.class.php 2013-03-05
// +----------------------------------------------------------------------

namespace CLib\Image;

c_lib()->load('image');

use CLib\Image;
use CLib\ImageInterface;

class Gd implements ImageInterface{
	/**
	 * 图像资源对象
	 * @var resource
	 */
	private $img;

	/**
	 * @var GIF
	 */
	private $gif = NULL;

	/**
	 * 图像信息，包括width,height,type,mime,size
	 * @var array
	 */
	private $info;

	/**
	 * 构造方法，可用于打开一张图像
	 * @param string $imgname 图像路径
	 */
	public function __construct($imgname = NULL){
		$imgname && $this->open($imgname);
	}

	/**
	 * 打开一张图像
	 * @param  string $imgname 图像路径
	 * @throws \Exception
	 */
	public function open($imgname){
		//检测图像文件
		if(!is_file($imgname)){
			throw new \Exception(_('The image file does not exist'));
		}

		//获取图像信息
		$info = getimagesize($imgname);

		//检测图像合法性
		if(false === $info || (IMAGETYPE_GIF === $info[2] && empty($info['bits']))){
			throw new \Exception(_('Illegal image file'));
		}

		//设置图像信息
		$this->info = array(
			'width' => $info[0],
			'height' => $info[1],
			'type' => image_type_to_extension($info[2], false),
			'mime' => $info['mime'],
		);

		//销毁已存在的图像
		empty($this->img) || imagedestroy($this->img);

		//打开图像
		if('gif' == $this->info['type']){
			c_lib()->load('image/GIF');
			$class = 'CLib\\Image\\GIF';
			$this->gif = new $class($imgname);
			$this->img = imagecreatefromstring($this->gif->image());
		} else{
			$fun = "imagecreatefrom{$this->info['type']}";
			$this->img = $fun($imgname);
		}
	}

	/**
	 * 保存图像
	 * @param  string  $imgname   图像保存名称
	 * @param  string  $type      图像类型
	 * @param  boolean $interlace 是否对JPEG类型图像设置隔行扫描
	 * @throws \Exception
	 */
	public function save($imgname, $type = NULL, $interlace = true){
		if(empty($this->img)){
			throw new \Exception(_('No image resources can be saved'));
		}

		//自动获取图像类型
		if(is_null($type)){
			$type = $this->info['type'];
		} else{
			$type = strtolower($type);
		}

		//JPEG图像设置隔行扫描
		if('jpeg' == $type || 'jpg' == $type){
			$type = 'jpeg';
			imageinterlace($this->img, $interlace);
		}

		//保存图像
		if('gif' == $type && !empty($this->gif)){
			$this->gif->save($imgname);
		} else{
			$fun = "image{$type}";
			$fun($this->img, $imgname);
		}
	}

	/**
	 * 返回图像宽度
	 * @return integer 图像宽度
	 * @throws \Exception
	 */
	public function width(){
		if(empty($this->img)){
			throw new \Exception(_('Not specified image resource'));
		}
		return $this->info['width'];
	}

	/**
	 * 返回图像高度
	 * @return integer 图像高度
	 * @throws \Exception
	 */
	public function height(){
		if(empty($this->img)){
			throw new \Exception(_('Not specified image resource'));
		}
		return $this->info['height'];
	}

	/**
	 * 返回图像类型
	 * @return string 图像类型
	 * @throws \Exception
	 */
	public function type(){
		if(empty($this->img)){
			throw new \Exception(_('Not specified image resource'));
		}
		return $this->info['type'];
	}

	/**
	 * 返回图像MIME类型
	 * @return string 图像MIME类型
	 * @throws \Exception
	 */
	public function mime(){
		if(empty($this->img)){
			throw new \Exception(_('Not specified image resource'));
		}
		return $this->info['mime'];
	}

	/**
	 * 返回图像尺寸数组 0 - 图像宽度，1 - 图像高度
	 * @return array 图像尺寸
	 * @throws \Exception
	 */
	public function size(){
		if(empty($this->img)){
			throw new \Exception(_('Not specified image resource'));
		}
		return array(
			$this->info['width'],
			$this->info['height']
		);
	}

	/**
	 * 裁剪图像
	 * @param  integer $w      裁剪区域宽度
	 * @param  integer $h      裁剪区域高度
	 * @param  integer $x      裁剪区域x坐标
	 * @param  integer $y      裁剪区域y坐标
	 * @param  integer $width  图像保存宽度
	 * @param  integer $height 图像保存高度
	 * @throws \Exception
	 */
	public function crop($w, $h, $x = 0, $y = 0, $width = NULL, $height = NULL){
		if(empty($this->img)){
			throw new \Exception(_('No image can be cropped resources'));
		}

		//设置保存尺寸
		empty($width) && $width = $w;
		empty($height) && $height = $h;

		do{
			//创建新图像
			$img = imagecreatetruecolor($width, $height);
			// 调整默认颜色
			$color = imagecolorallocate($img, 255, 255, 255);
			imagefill($img, 0, 0, $color);

			//裁剪
			imagecopyresampled($img, $this->img, 0, 0, $x, $y, $width, $height, $w, $h);
			imagedestroy($this->img); //销毁原图

			//设置新图像
			$this->img = $img;
		} while(!empty($this->gif) && $this->gifNext());

		$this->info['width'] = $width;
		$this->info['height'] = $height;
	}

	/**
	 * 生成缩略图
	 * @param  integer $width  缩略图最大宽度
	 * @param  integer $height 缩略图最大高度
	 * @param  integer $type   缩略图裁剪类型
	 * @throws \Exception
	 */
	public function thumb($width, $height, $type = Image::IMAGE_THUMB_SCALE){
		if(empty($this->img)){
			throw new \Exception(_('No image can be abbreviated Resources'));
		}

		//原图宽度和高度
		$w = $this->info['width'];
		$h = $this->info['height'];
		$x = $y = 0;

		/* 计算缩略图生成的必要参数 */
		switch($type){
			/* 等比例缩放 */
			case Image::IMAGE_THUMB_SCALE:
				//原图尺寸小于缩略图尺寸则不进行缩略
				if($w < $width && $h < $height){
					return;
				}

				//计算缩放比例
				$scale = min($width / $w, $height / $h);

				//设置缩略图的坐标及宽度和高度
				$x = $y = 0;
				$width = $w * $scale;
				$height = $h * $scale;
				break;

			/* 居中裁剪 */
			case Image::IMAGE_THUMB_CENTER:
				//计算缩放比例
				$scale = max($width / $w, $height / $h);

				//设置缩略图的坐标及宽度和高度
				$w = $width / $scale;
				$h = $height / $scale;
				$x = ($this->info['width'] - $w) / 2;
				$y = ($this->info['height'] - $h) / 2;
				break;

			/* 左上角裁剪 */
			case Image::IMAGE_THUMB_NORTHWEST:
				//计算缩放比例
				$scale = max($width / $w, $height / $h);

				//设置缩略图的坐标及宽度和高度
				$x = $y = 0;
				$w = $width / $scale;
				$h = $height / $scale;
				break;

			/* 右下角裁剪 */
			case Image::IMAGE_THUMB_SOUTHEAST:
				//计算缩放比例
				$scale = max($width / $w, $height / $h);

				//设置缩略图的坐标及宽度和高度
				$w = $width / $scale;
				$h = $height / $scale;
				$x = $this->info['width'] - $w;
				$y = $this->info['height'] - $h;
				break;

			/* 填充 */
			case Image::IMAGE_THUMB_FILLED:
				//计算缩放比例
				if($w < $width && $h < $height){
					$scale = 1;
				} else{
					$scale = min($width / $w, $height / $h);
				}

				//设置缩略图的坐标及宽度和高度
				$neww = $w * $scale;
				$newh = $h * $scale;
				$posx = ($width - $w * $scale) / 2;
				$posy = ($height - $h * $scale) / 2;

				do{
					//创建新图像
					$img = imagecreatetruecolor($width, $height);
					// 调整默认颜色
					$color = imagecolorallocate($img, 255, 255, 255);
					imagefill($img, 0, 0, $color);

					//裁剪
					imagecopyresampled($img, $this->img, $posx, $posy, $x, $y, $neww, $newh, $w, $h);
					imagedestroy($this->img); //销毁原图
					$this->img = $img;
				} while(!empty($this->gif) && $this->gifNext());

				$this->info['width'] = $width;
				$this->info['height'] = $height;
				return;

			/* 固定 */
			case Image::IMAGE_THUMB_FIXED:
				$x = $y = 0;
				break;

			default:
				throw new \Exception(_('Does not support the type of crop thumbnails'));
		}

		/* 裁剪图像 */
		$this->crop($w, $h, $x, $y, $width, $height);
	}

	/**
	 * 添加水印
	 * @param  string  $source 水印图片路径
	 * @param  integer $locate 水印位置
	 * @param  integer $alpha  水印透明度
	 * @throws \Exception
	 */
	public function water($source, $locate = Image::IMAGE_WATER_SOUTHEAST, $alpha = 80){
		//资源检测
		if(empty($this->img)){
			throw new \Exception(_('No watermark can be added to image resources'));
		}
		if(!is_file($source)){
			throw new \Exception(_('Watermark image absence'));
		}

		//获取水印图像信息
		$info = getimagesize($source);
		if(false === $info || (IMAGETYPE_GIF === $info[2] && empty($info['bits']))){
			throw new \Exception(_('Illegal watermark file'));
		}

		//创建水印图像资源
		$fun = 'imagecreatefrom' . image_type_to_extension($info[2], false);
		$water = $fun($source);

		//设定水印图像的混色模式
		imagealphablending($water, true);

		/* 设定水印位置 */
		switch($locate){
			/* 右下角水印 */
			case Image::IMAGE_WATER_SOUTHEAST:
				$x = $this->info['width'] - $info[0];
				$y = $this->info['height'] - $info[1];
				break;

			/* 左下角水印 */
			case Image::IMAGE_WATER_SOUTHWEST:
				$x = 0;
				$y = $this->info['height'] - $info[1];
				break;

			/* 左上角水印 */
			case Image::IMAGE_WATER_NORTHWEST:
				$x = $y = 0;
				break;

			/* 右上角水印 */
			case Image::IMAGE_WATER_NORTHEAST:
				$x = $this->info['width'] - $info[0];
				$y = 0;
				break;

			/* 居中水印 */
			case Image::IMAGE_WATER_CENTER:
				$x = ($this->info['width'] - $info[0]) / 2;
				$y = ($this->info['height'] - $info[1]) / 2;
				break;

			/* 下居中水印 */
			case Image::IMAGE_WATER_SOUTH:
				$x = ($this->info['width'] - $info[0]) / 2;
				$y = $this->info['height'] - $info[1];
				break;

			/* 右居中水印 */
			case Image::IMAGE_WATER_EAST:
				$x = $this->info['width'] - $info[0];
				$y = ($this->info['height'] - $info[1]) / 2;
				break;

			/* 上居中水印 */
			case Image::IMAGE_WATER_NORTH:
				$x = ($this->info['width'] - $info[0]) / 2;
				$y = 0;
				break;

			/* 左居中水印 */
			case Image::IMAGE_WATER_WEST:
				$x = 0;
				$y = ($this->info['height'] - $info[1]) / 2;
				break;

			default:
				/* 自定义水印坐标 */
				if(is_array($locate)){
					list($x, $y) = $locate;
				} else{
					throw new \Exception(_('Does not support the type of watermark location'));
				}
		}

		do{
			//添加水印
			$src = imagecreatetruecolor($info[0], $info[1]);
			// 调整默认颜色
			$color = imagecolorallocate($src, 255, 255, 255);
			imagefill($src, 0, 0, $color);

			imagecopy($src, $this->img, 0, 0, $x, $y, $info[0], $info[1]);
			imagecopy($src, $water, 0, 0, 0, 0, $info[0], $info[1]);
			imagecopymerge($this->img, $src, $x, $y, 0, 0, $info[0], $info[1], $alpha);

			//销毁零时图片资源
			imagedestroy($src);
		} while(!empty($this->gif) && $this->gifNext());

		//销毁水印资源
		imagedestroy($water);
	}

	/**
	 * 图像添加文字
	 * @param  string  $text   添加的文字
	 * @param  string  $font   字体路径
	 * @param  integer $size   字号
	 * @param  string  $color  文字颜色
	 * @param  integer $locate 文字写入位置
	 * @param  integer $offset 文字相对当前位置的偏移量
	 * @param  integer $angle  文字倾斜角度
	 * @throws \Exception
	 */
	public function text($text, $font, $size, $color = '#00000000', $locate = Image::IMAGE_WATER_SOUTHEAST, $offset = 0, $angle = 0){
		//资源检测
		if(empty($this->img)){
			throw new \Exception(_('No image can be written to a text resources'));
		}
		if(!is_file($font)){
			throw new \Exception(_("Font file does not exist:") . $font);
		}

		//获取文字信息
		$info = imagettfbbox($size, $angle, $font, $text);
		$minx = min($info[0], $info[2], $info[4], $info[6]);
		$maxx = max($info[0], $info[2], $info[4], $info[6]);
		$miny = min($info[1], $info[3], $info[5], $info[7]);
		$maxy = max($info[1], $info[3], $info[5], $info[7]);

		/* 计算文字初始坐标和尺寸 */
		$x = $minx;
		$y = abs($miny);
		$w = $maxx - $minx;
		$h = $maxy - $miny;

		/* 设定文字位置 */
		switch($locate){
			/* 右下角文字 */
			case Image::IMAGE_WATER_SOUTHEAST:
				$x += $this->info['width'] - $w;
				$y += $this->info['height'] - $h;
				break;

			/* 左下角文字 */
			case Image::IMAGE_WATER_SOUTHWEST:
				$y += $this->info['height'] - $h;
				break;

			/* 左上角文字 */
			case Image::IMAGE_WATER_NORTHWEST:
				// 起始坐标即为左上角坐标，无需调整
				break;

			/* 右上角文字 */
			case Image::IMAGE_WATER_NORTHEAST:
				$x += $this->info['width'] - $w;
				break;

			/* 居中文字 */
			case Image::IMAGE_WATER_CENTER:
				$x += ($this->info['width'] - $w) / 2;
				$y += ($this->info['height'] - $h) / 2;
				break;

			/* 下居中文字 */
			case Image::IMAGE_WATER_SOUTH:
				$x += ($this->info['width'] - $w) / 2;
				$y += $this->info['height'] - $h;
				break;

			/* 右居中文字 */
			case Image::IMAGE_WATER_EAST:
				$x += $this->info['width'] - $w;
				$y += ($this->info['height'] - $h) / 2;
				break;

			/* 上居中文字 */
			case Image::IMAGE_WATER_NORTH:
				$x += ($this->info['width'] - $w) / 2;
				break;

			/* 左居中文字 */
			case Image::IMAGE_WATER_WEST:
				$y += ($this->info['height'] - $h) / 2;
				break;

			default:
				/* 自定义文字坐标 */
				if(is_array($locate)){
					list($posx, $posy) = $locate;
					$x += $posx;
					$y += $posy;
				} else{
					throw new \Exception(_('Position of the character type is not supported'));
				}
		}

		/* 设置偏移量 */
		if(is_array($offset)){
			$offset = array_map('intval', $offset);
			list($ox, $oy) = $offset;
		} else{
			$offset = intval($offset);
			$ox = $oy = $offset;
		}

		/* 设置颜色 */
		if(is_string($color) && 0 === strpos($color, '#')){
			$color = str_split(substr($color, 1), 2);
			$color = array_map('hexdec', $color);
			if(empty($color[3]) || $color[3] > 127){
				$color[3] = 0;
			}
		} elseif(!is_array($color)){
			throw new \Exception(_('Wrong color values'));
		}

		do{
			/* 写入文字 */
			$col = imagecolorallocatealpha($this->img, $color[0], $color[1], $color[2], $color[3]);
			imagettftext($this->img, $size, $angle, $x + $ox, $y + $oy, $col, $font, $text);
		} while(!empty($this->gif) && $this->gifNext());
	}

	/* 切换到GIF的下一帧并保存当前帧，内部使用 */
	private function gifNext(){
		ob_start();
		ob_implicit_flush(0);
		imagegif($this->img);
		$img = ob_get_clean();

		$this->gif->image($img);
		$next = $this->gif->nextImage();

		if($next){
			$this->img = imagecreatefromstring($next);
			return $next;
		} else{
			$this->img = imagecreatefromstring($this->gif->image());
			return false;
		}
	}

	/**
	 * 析构方法，用于销毁图像资源
	 */
	public function __destruct(){
		empty($this->img) || imagedestroy($this->img);
	}
}